Fix tuple printing in error message of tuple routing for partitions

With correctly crafted DDLs, this could lead to disclosure of arbitrary
backend memory a user may have no right to access.  This impacts only
REL_11_STABLE, as the issue has been introduced by 34295b8.

On HEAD, add regression tests to cover this issue in the future.

Author: Michael Paquier
Reviewed-by: Noah Misch
Security: CVE-2019-10129

3 files changed, 26 insertions, 4 deletions

diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 8061c7e449d..0595d6bf1d6 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -329,10 +329,6 @@ ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
 		}
 	}
 
-	/* Release the tuple in the lowest parent's dedicated slot. */
-	if (myslot != slot)
-		ExecClearTuple(myslot);
-
 	/* A partition was not found. */
 	if (result < 0)
 	{
@@ -348,6 +344,10 @@ ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
 				 val_desc ? errdetail("Partition key of the failing row contains %s.", val_desc) : 0));
 	}
 
+	/* Release the tuple in the lowest parent's dedicated slot. */
+	if (myslot != slot)
+		ExecClearTuple(myslot);
+
 	MemoryContextSwitchTo(oldcxt);
 	ecxt->ecxt_scantuple = ecxt_scantuple_old;
 
diff --git a/src/test/regress/expected/insert.out b/src/test/regress/expected/insert.out
index 13f53e36490..2d909972ff3 100644
--- a/src/test/regress/expected/insert.out
+++ b/src/test/regress/expected/insert.out
@@ -637,6 +637,9 @@ create table mlparted5 partition of mlparted
   for values from (1, 40) to (1, 50) partition by range (c);
 create table mlparted5_ab partition of mlparted5
   for values from ('a') to ('c') partition by list (c);
+-- This partitioned table should remain with no partitions.
+create table mlparted5_cd partition of mlparted5
+  for values from ('c') to ('e') partition by list (c);
 create table mlparted5_a partition of mlparted5_ab for values in ('a');
 create table mlparted5_b (d int, b int, c text, a int);
 alter table mlparted5_ab attach partition mlparted5_b for values in ('b');
@@ -644,6 +647,12 @@ truncate mlparted;
 insert into mlparted values (1, 2, 'a', 1);
 insert into mlparted values (1, 40, 'a', 1);  -- goes to mlparted5_a
 insert into mlparted values (1, 45, 'b', 1);  -- goes to mlparted5_b
+insert into mlparted values (1, 45, 'c', 1);  -- goes to mlparted5_cd, fails
+ERROR:  no partition of relation "mlparted5_cd" found for row
+DETAIL:  Partition key of the failing row contains (c) = (c).
+insert into mlparted values (1, 45, 'f', 1);  -- goes to mlparted5, fails
+ERROR:  no partition of relation "mlparted5" found for row
+DETAIL:  Partition key of the failing row contains (c) = (f).
 select tableoid::regclass, * from mlparted order by a, b, c, d;
   tableoid   | a | b  | c | d 
 -------------+---+----+---+---
@@ -660,6 +669,12 @@ alter table mlparted drop e;
 insert into mlparted values (1, 2, 'a', 1);
 insert into mlparted values (1, 40, 'a', 1);  -- goes to mlparted5_a
 insert into mlparted values (1, 45, 'b', 1);  -- goes to mlparted5_b
+insert into mlparted values (1, 45, 'c', 1);  -- goes to mlparted5_cd, fails
+ERROR:  no partition of relation "mlparted5_cd" found for row
+DETAIL:  Partition key of the failing row contains (c) = (c).
+insert into mlparted values (1, 45, 'f', 1);  -- goes to mlparted5, fails
+ERROR:  no partition of relation "mlparted5" found for row
+DETAIL:  Partition key of the failing row contains (c) = (f).
 select tableoid::regclass, * from mlparted order by a, b, c, d;
   tableoid   | a | b  | c | d 
 -------------+---+----+---+---
diff --git a/src/test/regress/sql/insert.sql b/src/test/regress/sql/insert.sql
index 4d1c92a54df..23885f638c0 100644
--- a/src/test/regress/sql/insert.sql
+++ b/src/test/regress/sql/insert.sql
@@ -409,6 +409,9 @@ create table mlparted5 partition of mlparted
   for values from (1, 40) to (1, 50) partition by range (c);
 create table mlparted5_ab partition of mlparted5
   for values from ('a') to ('c') partition by list (c);
+-- This partitioned table should remain with no partitions.
+create table mlparted5_cd partition of mlparted5
+  for values from ('c') to ('e') partition by list (c);
 create table mlparted5_a partition of mlparted5_ab for values in ('a');
 create table mlparted5_b (d int, b int, c text, a int);
 alter table mlparted5_ab attach partition mlparted5_b for values in ('b');
@@ -416,6 +419,8 @@ truncate mlparted;
 insert into mlparted values (1, 2, 'a', 1);
 insert into mlparted values (1, 40, 'a', 1);  -- goes to mlparted5_a
 insert into mlparted values (1, 45, 'b', 1);  -- goes to mlparted5_b
+insert into mlparted values (1, 45, 'c', 1);  -- goes to mlparted5_cd, fails
+insert into mlparted values (1, 45, 'f', 1);  -- goes to mlparted5, fails
 select tableoid::regclass, * from mlparted order by a, b, c, d;
 alter table mlparted drop d;
 truncate mlparted;
@@ -425,6 +430,8 @@ alter table mlparted drop e;
 insert into mlparted values (1, 2, 'a', 1);
 insert into mlparted values (1, 40, 'a', 1);  -- goes to mlparted5_a
 insert into mlparted values (1, 45, 'b', 1);  -- goes to mlparted5_b
+insert into mlparted values (1, 45, 'c', 1);  -- goes to mlparted5_cd, fails
+insert into mlparted values (1, 45, 'f', 1);  -- goes to mlparted5, fails
 select tableoid::regclass, * from mlparted order by a, b, c, d;
 alter table mlparted drop d;
 drop table mlparted5;